That just sounds like "everyone else is smoking, so I should start smoking too". Just because everyone else is doing it does not mean it is the right thing for you to do.
In this instance, if developing friendships relies on me sending my data to some unknown person the other side of the world so that they can build graphs on my activity and follow me around just because everyone else has decided that's what they want to do, then I would choose another path.
Wouldn't you? If not, please send me all your data and details of your activities, all the time. If you can trust that data to some guy you've never met in a datacenter, then why not send it to me. You've got my username - that's more than you'll ever know about the people looking at your data at Facebook.